Herpes simplex virus further explored in AE

Many autoimmune encephalitis survivors and family members long to know what caused the illness. Some causes are known, some are not. Among the known causes of anti-NMDA AE are ovarian teratomas and a few viruses, particularly the herpes simplex virus. Studies have shown some patients who develop herpes simplex encephalitis (HSE) go on to develop AE. Dr. Armangue and others recently published a study in The Lancet, conducted at 19 hospitals in Spain. They found a significant percentage of patients with HSE went on to develop autoimmune encephalitis (27%), often within 2 months. Children were more likely to be affected; many patients benefited from immunotherapy so early detection is important.

A surprising result of the study was the significant number of patients who did not develop AE, but went on to develop antibodies to NMDA receptors or other unknown antigens within a year. In a comment by Dr. Gelfand of the University of California at San Francisco concerning this study he noted, “These findings suggest that development of autoantibodies to neuronal cell-surface targets like NMDAR might be necessary but is not sufficient to cause antibody-mediated autoimmune encephalitis without other contributing factors.” He mentioned the possibility of looking into genetic risk factors as an area needing further research. Additionally, he stated that study of these processes at a molecular level will be helpful in learning about the various causes of AE and therefore in developing future treatments.